The field of portable devices is a competitive one and it is generally desirable for manufacturers to produce designs that are both aesthetically appealing and user-friendly. Mobile communications handsets are known which include multicolour displays, illumination effects within the casing of the handset, or multicolour plastic casings. In order to make a portable device distinctive it would be desirable to produce such a device having an illumination arrangement significantly different from previously known devices, and preferably having an illumination arrangement capable of improving the user-friendliness of the device.